While I still personally consider GTA IV to be the most overrated game of all time, the series doesn't need "reviving" by any stretch. It just needs to better understand whatever the hell it's trying to be.
I loved the gritty nature of IV and the more down to earth approach, I just hated the terrible central characters, the story that went nowhere, and the inconsistancy of the whole affair. And, for the love of god, give us more things to DO.
If they can re-create San Andreas with IV's production values and grit, they'll have a real contender for the Best Game Ever award. Until then, San Andreas is still the best GTA.